فصلنامه علوم و فناوری دریا
سال هجدهم شماره 70 (تابستان 1393)

High Speed Crafts due to their high speed have a unique geometrical configuration، and light weight materials such as aluminium alloys and composite materials is used in their structures. on the other hand، these vessels due to high speed and significant maneuverability have exposed to many hydrodynamic loads as slamming pressure. Hence، structural analysis of these crafts under affected loads is very important. among this، aluminium alloys because of many advantages are extensively used in high speed crafts. Also monohull high speed crafts due to simple construction process relative to other high speed crafts are more attended by manufacturers. Purpose of this project is modeling of aluminiummonohull high speed crafts and finite element analysis of them in ANSYS finite element software. for the simplicity of modeling and analysis of considered crafts، a program is written. The written program is used for creation of input macro of ansys software and is contained modeling and analysis procedure on the basis of assumptions and simplifications. For the modeling and structural analysis process of high speed crafts and then evaluation of them، classification rules through program creation is utilized. It is important to say that written program for production of input macro of ansys software is provided in MATLAB software.

Due to the development of portsand coastal structures، application of breakwaters as a manner to deal with the wave loads، play an important role for making a shelter for ships to anchor. In this research، the stability of Nowshahr Port breakwaters has been investigated by utilizing Van der Meer formula، which made more accurate results in comparison with Hudson approach. Environmental parameters and regional impacts were considered as well. The results of the two methods compared and new. techniques for constructing breakwaters with enhanced stability and performance are proposed.

Changes in physiological، biochemical and histological to estimate the influence of living organisms، chemicals and environmental pollutants has become increasingly important. These changes reflect the changes in biomarkers that are being identified. Biomarkers can be based on the type and characteristics of its various surfaces such as cellular، molecular، population and ecosystem are discussed. According to researchers biomarkers can be categorized into two types based on the application and the response of organisms to anti-life substances. Usually the concentration of pollutants in the environment studied is much lower than the detection limit of the laboratory measurement instruments. So without the Signs of pollution، the effects of these substances on live components can be recognized. Biological markers (biomarkers) based ondiversity، their application can be effective and the sensible characteristics that can make them as the monitoring tools in variety of science are specificity، sensitivity and practicality.

Position tracking control of robot manipulator is done in two method as joint space control and task space control. In operating robot manipulators in marine industries، due to the complexity and limitations in task space، the effect of uncertainties on the performance of the robot manipulator increases. Therefore، desirable control in joint space، necessarily does not lead to desirable control in task space. On the other hand، using of Jacobian matrix inverse for calculating the dynamic equations of robot manipulator in task space، will encounter the task space control to the problem of singular points. In proposed approach، Jacobin matrix transpose rather than the Jacobin matrixreverse is used. Finally، crossing the singular points by design of a variable structure controller will be possible.

Portsareconsidered asthe connection pointsof the world tradeinallmaritime countries. Hence، issue such aswaiting times andservicetimesof thevessels are considered very importance. On this basis of this in the congestedports، loading and unloading of vessels may take months in the queues due to the lack of loading facilities. In fact ports are considered as a queuing system characterized with basic parameters: the vessels arrival rate and the ship service at an observed unit of time. The appropriate indices of the port operations are computed on the basis of these parameters. Thisresearchhas described theapplication ofqueueing theoryfor improving theport''soperationsin order to reducewaiting timesof the vessels. On the basis of this study، it can beconclude thatqueuing theorycandeterminethe appropriateinputpattern، analysequeuingsystems، and reducewaiting times of vesselsreadyto be served in order to increase the throughput ofports.

Flooding resulting from hurricanes and other extreme storm events is aprominent risk along the coasts. These coastal areas are typically of low elevation and relief، making land and infrastructure highly susceptible to inundation by storm surge and waves. Theseverity of this threat is exacerbated by sea level rise and a possible increase in storm frequencyand strength due to climate change. Although hard protection structures such as levees and floodwalls reduce flood risk، these structures may fail when storm conditions exceed the designthreshold. There is a general consensus that wetlands، which often serve as transition zonesbetween open water and dry land، could act as buffers and reduce storm surge and propagatingwaves substantially before they encounter coastal development. Unfortunately، the capability of wetlands to serve as protection during extreme storms is not understood fully or welldocumented; furthermore، water level and wave height reductions by vegetation are studied onlyin low-energy environments. Nonetheless، these studies present methods to quantify vegetation-induced wave attenuation for both modeling and design. This technical note focuses on thedamping of propagating water waves by vegetation، but also discusses surge reduction briefly. Although waves may be encountered in freshwater environments (e. g.، boat wakes، lake fetch، flood waves، etc.)، this review focuses on coastal vegetation and resultant effects on flood and storm damage reduction.